A ketal can be prepared by condensing an alcohol with a ketone. The ketal forming reaction is often carried out in a solvent such as benzene or toluene in the presence of an acid catalyst such as p-toluenesulfonic acid. The ketal forming reaction is typically driven to completion by azeotropic removal of water from the reaction mixture as the water is formed by the condensation of the diol with the ketone. One drawback with such a synthetic method is the need to remove water from the reaction mixture as it is formed in order to drive the reaction to completion. Another drawback is that, in order to remove the water from the reaction mixture, the solvent must be capable of forming an azeotrope with water and, typically, such solvents include benzene and toluene, which are considered to be hazardous and require certain handling precautions.
There exists a need for improved synthetic methods that readily provide ketals without the drawbacks associated with the azeotropic removal of water from the reaction mixture. The present invention seeks to fulfill these needs and provides further related advantages.